import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';

//白名单
const CATCH_URLS = ['m.ctrip.com/','m.ctrip.com/html5/','m.ctrip.com/html5'];

class WebView extends StatefulWidget {

  final String url;
  final String statusBarColor;
  final String title;
  final bool hideAppBar;
  final bool backForbid;

  const WebView({Key key, this.url, this.statusBarColor, this.title, this.hideAppBar, this.backForbid=false}) : super(key: key);

  @override
  _WebViewState createState() => _WebViewState();
}

class _WebViewState extends State<WebView> {

  bool exiting = false;

  final webviewReferrence = FlutterWebviewPlugin();
  StreamSubscription<String> _onUrlChanged;
  StreamSubscription<WebViewStateChanged> _onStateChanged;
  StreamSubscription<WebViewHttpError> _onHttpError;

  @override
  void initState() {
    super.initState();
    webviewReferrence.close();
    webviewReferrence.onUrlChanged.listen((String url) {

    });
    webviewReferrence.onStateChanged.listen((WebViewStateChanged state) {
      switch(state.type) {
        case WebViewState.startLoad:
        if(_isToMain(state.url)&&!exiting){
          if (widget.backForbid){
            webviewReferrence.launch(widget.url);
          } else {
            Navigator.pop(context);
            exiting = true;
          }
        }
        break;
        default:
        break;
      }
    });
    webviewReferrence.onHttpError.listen((WebViewHttpError error){
      print(error);
    });
  }

  _isToMain(String url) {
    bool contain = false;
    for(final value in CATCH_URLS) {
      if(url?.endsWith(value)??false) {
        contain = true;
        break;
      }
    }
    return contain;
  }

  @override
  void dispose() {
    _onHttpError.cancel();
    _onStateChanged.cancel();
    _onUrlChanged.cancel();
    webviewReferrence.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {

    String statusBarColorStr = widget.statusBarColor ?? 'ffffff';
    Color backButtonColor;
    if (statusBarColorStr == 'ffffff') {
      backButtonColor = Colors.black;
    } else {
      backButtonColor = Colors.white;
    }

    return Scaffold(
      body: Column(
        children: [
          _appBar(Color(int.parse('0xff'+statusBarColorStr)), backButtonColor),
          Expanded(
            child: WebviewScaffold(url: widget.url,
              withLocalStorage: true,
              hidden: true,
              initialChild: Container(
                color: Colors.white,
                child: Center(
                  child: Text('waiting...'),
                ),
              ),
            ),
          )
        ]
      ),
    );
  }

  _appBar(Color backgroundColor, Color backButtonColor) {
    if(widget.hideAppBar??false) {
      return Container(
        color: backgroundColor,
        height: 30
      );
    }
    return Container(
      color: backgroundColor,
      padding: EdgeInsets.fromLTRB(0, 40, 0, 10),
      child: FractionallySizedBox(
        widthFactor: 1,
        child: Stack(
          children: <Widget>[
            GestureDetector(
              onTap: () {
                Navigator.pop(context);
              },
              child: Container(
                margin: EdgeInsets.only(left: 10),
                child: Icon(
                  Icons.close,
                  color: backButtonColor,
                  size: 26,
                ),
              ),
            ),
            Positioned(
              left: 0,
              right: 0,
              child: Center(
                child: Text(widget.title??'',
                  style: TextStyle(color: backButtonColor, fontSize: 20),
                ),
              ),
            )
          ],
        ),
      )
    );
  }
}